Metallic frame for chairs with tubular elements

ABSTRACT

A metallic frame for chairs with tubular elements, comprising two inverted V-shaped elements that form the legs of a chair, which are parallel and joined substantially at their inside curvature to a rod-like crossmember, two L-shaped elements connected by the crossmember on which they are arranged in a parallel configuration so as to form a support for the back and for the seat, respectively with their first portions, which are substantially vertical, and second portions, which are substantially horizontal.

The present invention relates to a metallic frame for chairs withtubular elements.

Chairs with welded tubular elements are currently widespread which areof the type comprising two inverted U-shaped elements that form thelegs, two L-shaped elements that form a support for the back and theseat, and two horizontal and mutually parallel rod-like crossmembersthat join the inverted U-shaped elements and the L-shaped elements.

These elements are often joined by gas welding with the addition ofmaterial, and this entails rather long times to be dedicated to theassembly of the chairs and the consumption of added material forwelding, as well as associated high costs.

A solution aiming at overcoming these drawbacks is proposed with theteaching contained in WO02054913 in the name of this same Applicant.This application proposes to replace welding with added material withwelding of the projection type, thus reducing production costs and timesin addition to reducing the weight of the frame, facilitating thereforeits movement and transport. According to the teachings of the patent,the projection welding is performed advantageously at pairs of raisedportions formed by recesses of the cross-section of the tubularelements.

However, since market demand for this kind of chair is rather high, thenumber of components to be assembled affects heavily the finalproduction costs and the need is felt, therefore, to reduce these costsfurther and to also reduce further the production times, tryingnonetheless to obtain a frame whose solidity is comparable to thepreceding ones.

This type of structure is also designed so that it can be stacked easilyfor storage and transport on pallets.

The possibility of vertical stacking is achieved by superimposing theframes and alternating them turned by 90° with respect to each other.Currently, the need is also felt to increase the number of stackedchairs that can be transported, i.e., to increase their total numberthat can be carried within the same volume of a pallet in order toreduce the associated transport costs.

Another drawback is due to the fact that the inverted U-shaped elements,which constitute the legs of the chair for resting the frame on thefloor, due to their very shape and to the distance between the frontlegs and the rear legs, are unable to ensure stable resting even whenthe chair is in use, i.e., to exclude the risk of tipping, because theback typically protrudes from the rear part of the chair with respect tothe rear legs.

The aim of the present invention is to provide a metallic frame forchairs with tubular elements that is lighter than known frames andtherefore can be handled more easily by a user and, when stacked withother identical frames, occupies with them a smaller volume than knownframes.

Within this aim, an object of the invention is to provide a frame thatis at least as solid as currently commercially available frames and thatin particular is not subject to tipping problems.

Another object of the invention is to reduce the transport costs offrames for chairs with tubular elements.

Another object of the invention is to obtain a chair that has adifferent visual impact than known chairs.

This aim, as well as these and other objects which will become moreapparent hereinafter, are achieved by a metallic frame for chairs withtubular elements, characterized in that it comprises two invertedV-shaped elements that form the legs of a chair, which are parallel andjoined substantially at their inside curvature to a rodlike crossmember,two L-shaped elements connected by said crossmember on which they arearranged in a parallel configuration so as to form a support for theback and for the seat, respectively with their first portions, which aresubstantially vertical, and second portions, which are substantiallyhorizontal.

Further characteristics and advantages of the invention will become moreapparent from the description of a preferred but not exclusiveembodiment of the frame according to the invention, illustrated by wayof non-limiting example in the accompanying drawings, wherein:

FIG. 1 is a perspective view of a frame according to the invention;

FIG. 2 is an enlarged-scale view of a detail of the frame of FIG. 1;

FIG. 3 is a view of a detail of a portion of an L-shaped element;

FIG. 4 is an enlarged-scale view of a detail of a portion of an invertedV-shaped element;

FIG. 5 is an enlarged-scale view of another detail of another portion toof an inverted V-shaped element;

FIG. 6 is a side view of the frame according to the invention;

FIG. 7 is a front view of the frame according to the invention;

FIG. 8 is a top view of the frame according to the invention;

FIG. 9 is a perspective view of two frames according to the invention,stacked vertically according to a first stacking method;

FIG. 10 is a perspective view of a column of frames according to theinvention, stacked vertically with a second stacking method;

FIG. 11 is a top view of four columns of frames stacked according to themethod of FIG. 10.

With reference to the cited figures, the frame, generally designated bythe reference numeral 10, is formed by tubular elements 11, the mutualassociation of which is provided by welding.

The frame 10 as a whole is shown in FIG. 1. It comprises two invertedV-shaped elements 12, which form the legs of the chair, and two L-shapedelements 13, which form a support for the back and the seat.

The two inverted V-shaped elements 12 are parallel and are joinedsubstantially at their inside curvature 14, shown in detail in FIG. 4,to a rodlike crossmember 15. The L-shaped elements 13 are connected bythe crossmember 15 and are joined to it again by welding and arearranged thereon in a parallel configuration. In particular, they form asupport for the back with their first portions 16, which aresubstantially vertical, and form a support for the seat with theirsecond portions 17, which are substantially horizontal and mutuallyparallel.

FIG. 2 is an enlarged-scale view of the frame on the joining regions ofan inverted V-shaped element 12 and of an L-shaped element to thecrossmember 15.

Each one of the inverted V-shaped elements 12 has a first pair of raisedportions 18, at the inside curvature 14, which is formed by acorresponding first recess 19 of the cross-section obtained with aplastic compression deformation. Said first recess 19 is provided sothat upon V-shaped bending the excess material does not form wrinkles inthe region of the inside curvature 14.

The first pair of raised portions 18 and the first recess 19 are visiblein the enlarged-scale view of FIG. 4. Joining by welding occurs in theregions of contact of the first pair of raised portions 18 with thecrossmember 15, which consist of at least four points, but welding canextend, depending on the shape of the inside curvature 14 and of thecrossmember 15, up to one or two parallel lines that correspond to thetwo raised portions.

Each one of the L-shaped elements 13 advantageously has a second pair ofraised portions 20, formed by a corresponding second recess 21 on thelower side of the second portion 17 and so as to correspond to theregion for joining to the crossmember 15. The second pair of raisedportions 20 is also provided specifically by plastic compressiondeformation and produces a localized contact region at which weldingwith the crossmember 15 occurs.

Advantageously, each one of the L-shaped elements 13 also has anadditional pair of raised portions 22 at the curvature region 23, whichare formed by an additional recess 24 that is also obtained by plasticcompression deformation, again to prevent that, as a consequence of thebending, the curvature region 23 of the L-shaped element 13 has wrinklescaused by an excess of material in the regions having a smaller radius.

The first portions 16 and the second portions 17 of the L-shapedelements conveniently have a flattened cross-section, in order to givethe back and the seat a larger contact surface, and it can be noted, inparticular from the perspective view shown in FIG. 1 and from the topview of FIG. 8, that the first supporting portions 16 of the back arealso rotated, adapting to the curvature of the back to be associatedwith the frame in order to compose the chair.

The crossmember 15 has an oval cross-section that can be seen clearly inFIG. 5, with, in a sectional view, parallel sides 25, joined bysemicircular elements 26, which form two parallel faces of the samecrossmember 15. Joining by welding with each one of the invertedV-shaped elements 12 and with each one of the L-shaped elements 13occurs at the uppermost face of the two parallel faces.

The L-shaped elements 13 are joined by welding along at least one raisedportion of the second pair of raised portions 20.

As can be seen in FIG. 1 and in particular in the front view of FIG. 7,the crossmember 15 is substantially rectilinear and therefore thewelding of each one of the L-shaped elements 13 occurs at two parallellines that are formed by the respective second pair of raised portions20, which are intended for contact with the crossmember 15. However, ifthe crossmember 15 is not rectilinear but has for example a curvature ora bend in a downward direction that is contoured to the shape of theseat, the weld might still be performed validly in the same regions oralong a single raised portion of the second pair of raised portions 20.

It should be noted that the oval cross-section of the crossmember 15allows welding the elements on larger regions of contact than in thecase of the crossmember with circular cross-section as in known frames,making the weld more effective and durable.

Conveniently, as can be seen in the enlarged-scale view of FIG. 5, eachinverted V-shaped element 12 has a reinforcement recess 27 on the innerpart of each one of the two rectilinear portions 28 that formrespectively a front leg 29 and a rear leg 30 of the chair.

The reinforcement recess 27, as is clearly visible, extends practicallyalong the entire length of the leg and becomes gradually shallower in anupward direction. As shown in FIG. 9, in the stacking of the frames 10the internal surface of the rectilinear portion 28 of each front leg 29a or rear leg 30 a of a frame 10 a is coupled to the outer surface ofthe underlying leg, respectively the front leg 29 b or the rear leg 30b, of the underlying frame 10 b.

By way of non-limiting example, an angular aperture of the invertedV-shaped elements 12 of approximately 52° is to be preferred; an angleof approximately 109° between the first portion 16 and the secondportion 17 is instead to be preferred, again merely by way of example,for the inclination of the L-shaped elements 13.

With these solutions, the front legs 29 and the rear legs 30 of theframe 10 form, with their four resting points 33 at the base, a restingarea 34, shown in broken lines in FIG. 1, within which every point ofthe L-shaped elements 13 lies.

Once the back is assembled, the back fitted on the L-shaped elements 13also is such that every point thereof lies within the resting area 34.These refinements allow producing a chair that is capable of passing anytipping prevention tests.

Each L-shaped element 13 is provided conveniently, at its second portion17, with a hole 31 for fixing the seat of the chair by means of screws.The back can be associated easily with the frame 10, for example bymaking it slide from above onto the two first portions 16, so that theyenter adapted guides in said back.

The use of the frame according to the invention, in its stacking withother similar structures, is as follows.

The frame 10 can be stacked according to two possible stacking methods.

The first method is shown in FIG. 9 and the resulting configuration isdesignated by the reference letter A to distinguish it from a differentconfiguration of stacked frames 10, which can be obtained with a secondmethod shown in the subsequent FIGS. 10 and 11 and is designated here bythe reference letter B.

With the first stacking method, the frames 10 are superimposedvertically on each other according to the same orientation.

The inverted V-shaped elements 12 are inserted into each other and thereinforcement recesses 27, which make the internal surface of therectilinear portion 28 of each front leg 29 a or rear leg 30 a mate withthe outer surface of the underlying leg, respectively the front leg 29 bor the rear leg 30 b, ensure stable and aligned stacking of the frames10. With the second stacking method, the frames 10, other than with thepreceding method, are superimposed vertically so that they arealternated with an orientation of 90° of one with respect to thefollowing one. The stability of the stack of frames 10 is determined bythe coupling of the internal surface of each front leg 29 a or rear leg30 a of the frame 10 a with the external surface of the underlying leg,the front one 29 b or the rear one 30 b, which is the leg of the frame10 b that is arranged with the same orientation and is spaced from theupper frame 10 a by an intermediate frame 10 a that is rotated by 90°.

By repeating the stacking for a larger number of frames 10, one obtainsthe column 32 of frames 10 shown in FIG. 10.

By grouping four columns 32 of frames 10 stacked according to theconfiguration B described above it is possible to fill a pallet withoutwasting space, as shown in FIG. 11.

By way of example, it has been found that a pallet with maximum externaldimensions of 115 cm×110 cm×235 cm can contain 56% more frames 10 thanthe traditional product.

It should be noted that with respect to known frames, since the legs areformed by an inverted V-shaped element 12 with flattened regionsproduced by reinforcement recesses 27 on the internal part over theentire length of the legs 29 and 30, the line of the frame 10 isslenderer, as can be seen in particular in the side view of FIG. 6, andis aesthetically new with respect to known chairs with U-shapedelements. At the same time, again thanks to the reinforcement recesses27, the frame 10 is also stronger and the stacking possibility isimproved.

Moreover, the presence of a single crossmember 15 having an ovalcross-section allows not only welding the components at larger regionsof contact than would be the case with a circular cross-section, butalso makes it possible to save material and to obtain a frame that islighter and therefore easier to handle and transport than a frameprovided with two crossmembers.

The difference in weight of course becomes more evident when the framesare stacked and grouped in large numbers in pallets for transport.

In practice it has been found that the invention achieves the intendedaim and objects, providing a metallic frame for chairs with tubularelements that is lighter than known frames and therefore can be handledmore easily and allows reducing and containing production times as wellas production and transport costs.

The cost reduction in fact arises from the smaller amount of material tobe used to provide the frame and from better utilization of the volumeof the pallet by insertion of a larger number of frames therein.

Moreover, the frame is stable both when in use, provided with a seat anda back, passing anti-tipping tests, and when stacked with otheridentical frames, according to both configurations A and B.

Moreover, the frame has a different visual impact than traditional ones.

The invention thus conceived is susceptible of numerous modificationsand variations, all of which are within the scope of the appendedclaims; all the details may further be replaced with other technicallyequivalent elements.

In practice, the materials used, so long as they are compatible with thespecific use, as well as the contingent shapes and dimensions, may beany according to the requirements and the state of the art.

The disclosures in Italian Patent Application no. PD2013A000084, fromwhich this application claims priority, are incorporated herein byreference.

1-10. (canceled)
 11. A metallic frame for chairs with tubular elements,comprising two inverted V-shaped elements that form the legs of a chair,which are parallel and joined substantially at their inside curvature toa rod-like crossmember, two L-shaped elements connected by saidcrossmember on which they are arranged in a parallel configuration so asto form a support for the back and for the seat, respectively with theirfirst portions, which are substantially vertical, and second portions,which are substantially horizontal.
 12. The frame according to claim 11,wherein each one of said inverted V-shaped elements has a first pair ofraised portions formed by a corresponding first recess of thecross-section obtained from a plastic compression deformation at saidinside curvature.
 13. The frame according to claim 11, wherein each oneof said L-shaped elements has a second pair of raised portions, formedby a corresponding second recess of the cross-section obtained in adownward region on said second portion and so as to correspond to theregion for joining to said crossmember by plastic compressiondeformation.
 14. The frame according to claim 11, wherein each one ofsaid L-shaped elements has an additional pair of raised portions formedby a corresponding additional recess of the cross-section obtained byplastic compression deformation at its curvature region.
 15. The frameaccording to claim 11, wherein said crossmember is rectilinear with anoval cross-section with parallel sides, joined by semicircular elements,that form two parallel faces for said crossmember.
 16. The frameaccording to claim 12, wherein each one of said inverted V-shapedelements is joined to said crossmember by welding at regions of contactof said first pair of raised portions with said crossmember.
 17. Theframe according to claim 13, wherein each one of said L-shaped elementsis joined to said crossmember by welding at at least one raised portionof said second pair of raised portions.
 18. The frame according to claim11, wherein each one of said inverted V-shaped elements has areinforcement recess on the inner side of each one of two straightportions that form a front leg and a rear leg of said frame.
 19. Theframe according to claim 18, wherein it can be stacked with othersimilar frames, the possibility of stacking being determined by thecoupling of an internal surface of said rectilinear portion of eachfront leg or rear leg of one frame with the outer surface of arectilinear portion of each front leg or rear leg of an underlyingframe.
 20. The frame according to claim 11, wherein said front legs andsaid rear legs form, with their four resting points at the base, aresting area within which every point of the L-shaped elements lies.